The present invention relates to detecting the presence of a solute in a flowing fluid stream, herein called a carrier stream, upon the emergence of said carrier stream from a chromatographic column. More specifically, it relates to a detector for use in liquid chromatography. Liquid chromatography detectors are the subject of numerous patents, for example, Juvet et. al. U.S. Pat. No. 3,902,848, Broerman U.S. Pat. No. 3,513,319, Tesarik and Krejci U.S. Pat. No. 4,014,793, and Parkell and Stamm U.S. Pat. No. 4,019,372 and many publications, for example, L. R. Snyder, et. al., "Introduction to Modern Liquid Chromatography," John Wiley and Sons, New York, 1974.
An ideal detector will be both sensitive to small amounts of solute in the carrier stream and "universal" in that it can detect many types of compounds in the carrier stream. Detection based upon the absorption or emission (fluorescence) of light by the solute can be very sensitive, however, since each compound has its unique absorption and fluorescence spectrum, such detectors are not "universal". A frequently employed approach to designing a "universal" detector involves evaporating the carrier stream, i.e., the solvent, and then detecting the solute by some means such as for example, flame ionization. Such detectors can be quite "universal" and sensitive, but they are complex. Refractive index detectors are available and they are "universal" but very insensitive.